Those Igbo-Ukwu Glass Beads: Morphology, Chemistry, Provenance, and Trade

Abstract

Thurstan Shaw recovered more than 150,000 glass beads during his excavations at the famous site of Igbo-Ukwu which he meticulously sorted into morphological types. The geographic origin(s) of these beads and the presumed trade route(s) by which they reached the site have been the subject of debate. Here we report the results of chemical compositional analysis of 104 beads chosen to sample the diversity of the assemblage. Six chemical types of glass are identified, several of which were manufactured from raw materials in West Africa. We relate these both to their findspots in the site (Igbo Isaiah or Igbo Richard) and to Shaw’s bead types, new descriptions of which are provided here. A majority of the beads were made from plant-ash soda-lime glass, mostly manufactured in Mesopotamia but also in Egypt and possibly the Levant. This glass type predominates at Igbo Isaiah whereas a wider range of glass types, many of West African (Nigerian) origin, were found at Igbo Richard. Some of Shaw’s morphological bead types were made from more than one chemical type of glass; different glass chemical types may have been pooled in making some batches of beads indicating that many beads, including those of imported glass, were probably made or finished in the vicinity of Igbo-Ukwu and/or elsewhere in West Africa. These include some exquisitely decorated tiny beads likely made at or near Igbo-Ukwu by a highly skilled glassworker. The contextual and technological data provide insights into the chronology of Igbo-Ukwu and West African trade.